Receiving system for high-frequency electrical oscillations.



r. K. VREELAND. REGEIVING SYSTEM FOR. HIGH FREQUENCY ELEGTRIGAL OSOILLATIQNS. APPLICATION IILBD NOV. 4, 1905. 936,684. Patented Oct. 12, 1909.

UNITED srnrns PATENT OFFICE.

4 To all'whom it may concern:-

nnw voncx.

R, NEW JERSEY, ASSIGNOR T WIRELESS 01 NEW YORK, N. Y., A CORPORATION OF RECEIVING SYSTEM FOR HIGH-FREQUENCY E ECTRIC-AL SCILLATIQNSJ -Be it known that I, FREDERICK K. VREE- LAND, a citizen of the United States, residso that the current an alternating current of very in some other current however,

ing at Montclair, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Receiving Systems for High-Frequency Electrical' Oscillations, of which the following is a description.

The object of this invention is to increase the effective working current in a wireless telegraph or telephone receiver or receiving system, for the purpose of magnifying its effect on the detector or other translating device. The operation of this current multiplier is .based on the Well known princi le that in a system of conductors traversed by high frequency the princi a1 factor in controlling the distributlon oi the system is not theresistance of the conductors, as it is when continuous or low freuency alternating currents are used, but their inductance, and-that the currents in the system tend to distribute. themselves in such a manner'that the kinetic energy of thesystem as a whole shall be a minimum.

two. dissimilar coils of wire'wound in close inductive relation, produced by giving bers of turns,

the dissimilarity being the coils difi'erent numrespect, as in the relative a1"- rangement of the coils, sothat. the mutually interlinked flux will produce more electromctive. force in one coil than in the other.

The coils are connected in parallel in the circuit carryin'gthe current to be multiplied. These two. coils. are wound in the same di rection with relation to the main circuit, and are similarly connected in that circuit, in.- the circuit tends to produce in them magnetic fields which augment each other. The larger resultantv which flows through the local circuit formed by the two coils, progreater than this.

the current throughout or by making them dissimilar speciflcationofletters.Batent. P t t 0 1;, 12, 19 09., Application filed November 4, 19.05. Serial No. 285,862.

duces opposing fields in these coils, as will be presently explained.

Figure l hows diagrammatically such a allel in the circuit 3, 4 carrying the current to be. multiplied, which circuit 3, 4t is here represented as thegrounded antenna circuit of an ordinary wireless telegraph receiving system. The coill is illustrated as having three turns, and the coil 2 as having four turns, although in practice the number of turns'of each coil'should usually be much When so arranged, the currents in the coils 1, 2 will each. be greater than the current in the main circuit 3, 4, and at any given instant the currents in these two coils will flow in opposite directions, so that their algebraic sum, that is, the difference of their arithmetical values, is equal to the current in the circuit 3, 4:. A. detector or other translating device 5 may be placed in either of the branch circuits, though it is preferably placed in the one which has the pair of dissimilar coils l, 2 connected in parsmaller number of turns and hence thelarger current; or detectors may be placed in both branches. The detector is preferably one whose ohmic resistance is as low aspossible. The ap lication of the broad principle outlined a ove to this specific form of apparatus is as followszlf the current in 'the circuit 3, 4 were a continuous or low frequency alternating one, it would divide between the circuits 1, 2 in inverse proportion to their ohmic resistances. The result would be that the magnetic fields produced by the currents. in the two coils would overlap and augment each other, asv the currents would flow through the two. coils in the same direction... Consequently thekinetic energy of the field due to both coils together is greater than that of the field due to either. As the frequency of the current is increased, the

importance of the inductance of the system in determining; the current distribution be comes greater and greater, until at very high frequencies it. is the controlling factor, and

the ohmic resistance of the circuits becomes comparatively negligible. The tendency 1s,

as stated above, for the currnts to distribute themselves'between the two coils in such a manner that the energy of the resulting magnetic field shall be aminimum. Thisis accomplished when the currents in the 00118 stated above.

It Wlll be noted that the multiplying factor of the, device increases as the ratio of 1, 2 flow in opposite directions and are inversely proportional to the number of turns of their respective coils. Thus when the coil 1 has three turns and the coil 2 four turns, the current in the former will be 1 units and that in the latter 3 units, so that the resulting ampere turns of both coils will be zero; the current in the main circuit-3, 4, which is equal to the algebraic sum of the two branch currents, will then be 1 unit. 'Looking at the matter from another point of view, the system of two coils illustrated in Fig. 1 may be considered as'constituting a transformer short-circuited upon itself. Suppose for a momentthat the-current in the main circuit 3,4, which we will assume to have a value of 1 unit, divides equally between the coils 1, 2, each of which carries g unit: the result would be a magnetic flux interlinked between the two coils, and this alternating magnetic flux will induce an electromotive force in each coil. As the coil 2 has the greater number of turns, its electromotive' force will be greater than that of the coil 1, and the result will be a local current flowing throu h the circuit 1, 2 in the direction indicated y the arrows. The magnetic field due to this local current will oppose that due to the assumed initial current, and the limiting value of the local current is that at which the two fields neutralize each other. This occurs in the specific case assumed when the local current has a'value of 3% units; the current in'the coil 1 will'then be +3=4 units, and the current in the coil 2 will be 1 -3%=-3 units, and their algebraic sum is equal tothe main current, z'. e. 1 unit, as

turns in the two coils approaches unity. In the ideal case where the two coils have almost the same number of turns, the local cur rent would be almost infinite; but such a condition is obviously impossible in practice, for a point is eventually reached at which the ohmic resistance of the system begins to play an important part and destroys the effectiveness of the device. Hence it is. desirable to make the ohmic resistance as low as possible, and the self induction of each coil and their mutual induction as high as possible. To this'end the coils shou ably be wound on the same bobbin and in as close a mutualrelation as possible. I have found that the apparatus, when suitably designed and properl used, gives a multiplying effect practlca y equal to the full theoretical value; thus with two coils having a ratio of turns of to one.

- Fig. 2 shows'in cross-section a suitable 'arrangement in which the coil l'is divided into two sections having each twelve turns, and

d preferthree tofour, I have ob mined iplying factorof almost four' the coil 2 is divided into'two sections alternating with the section of the coil 1 and having each sixteen turns, the current entering at the middle of one section and leaving at the middle of the secondsection of each coil. The coils are shown for the sake of clearness as, having a comparatively small number of turns, though usually a larger number would be desirable.

The requirement of low ohmic resistance of the system applies also to the detector 5, which should preferably be of some low resistance type, such for example as one in which the mechanical action between two adjacent coils carrying high frequency alternating signal impulses is caused to produce an audible or otherwise observable signal. This detector may be connected in either of the branches of ,the multiplying device, as shown in Fig. 1-; or if desired, the functions of current multiplier and detector can be combined in one ap :i)aratus,'i. e. the coils 1' and 2 of Fig- 1 can e so arranged as to be relatively movable, and the mechanical forces between them may be utilized to produce the signah- Such an arrangement is shown in Fig. 3, which is a longitudinal section of a telephone form of detector, one coil is mounted upon a telephone diaphragm 6 of elastic insulating material, and

the other coil is immovably mounted adjacent to the first coil upon the insulatin body 7. The coils, while being wound, an connected in similar senses mechanically or structurally with relation to the main circuit, are in eifect wound oppositely with relation to the flow of the current through them, because their mutual inductive action produces in them currents flowing in o posite directions. The coils therefore pro uce magnetic fields which are mutually opposed, and such coils are arranged in close mductive relation, and the force producing the mechanical movement of the diaphragm is one of repulsion.

In Fig. 1 the current multiplier is shown,-

for the sake of clearness, connected in a simple antenna circuit, althou h it is obvious that it may be-used effectively in any receiver circuit carrying a high frequency current which it is desired -to multiply roin which vided the necessary conditions are in ed,

as already stated.

WhatIclaimis;

' '1. In a receiving system for high freuency electrical oscillations, a current multiplier com rising dissimilar coils traversed by the osci' lations and wound in close inductive relation, such coils actingon each other so asto reverse the current in one coil and thereby augment the current in the other coil, in combination withmeans for detecting the augmented oscillations, substantially as set fort 2. In a receiving system for high quency electrical oscillations, the combination of dissimilar coils wound in close in-' oscillations, and means for detecting the augmented oscillatioi'l's, forth.

3. In a receiving system for high frequency electrical oscillations, a combined receiver and current multiplier having in combination dissimilar coils traversed by the oscillations and woundin close inductive relation, such coils acting on each other so as to reverse the current in one coil and thereby augment the current in the other coil and being mounted so as to be relatively movable, and means for translating the relative movement of-the coils into observable signals, substantially as set forth.

In a receiving system for high fresubstantially as set quency electrical oscillations, the combination of dissimilar coils wound in close insigna-ls, substantially as set forth. 5. In a receiving s stem for high frethis second day of November, 1905.

ductive relation and connected in parallel and in the same sense in a circuit traversed by the oscillations, a support'for such coils permitting the relative movement of the coils, and means for translating such relative movement of the coils into observable quency electrical oscil ations, the combination of dlsslmllar colls wound m close inductive relation and connected in paralleland 'in the same sense in a circuit traversed by the oscillations, a. support for the coils permitting their relative movement, and a diaphragm aflected bysuch relative movement of'the coils to produce audiblesignals, substantially asset forth.

This specification signed .and witnessed FREDERICK K. VREELAND. Witnesses J NO. Roe'r. TAYLOR,-

JOHN S. ,Lorscn. 

